fortunately, smarter people than I took the troubleshooting. The problem was this:
The Network Admin decided to use a DHCP super scope on the Win2K server, with several DHCP subscopes ( one for each office ) underneath. He had understood that the purpose of the superscope was to pass values common to all subscopes - things like NTP server, DNS server, SMTP server - while things like the default gateway would remain with the sub scopes. Turns out this was a misunderstanding. The superscope ( apparently, if I understand what I am being told ) is only for segments where there are numbers of subnets on the same wire. This actually might explain why Microsoft tech support misunderstood what was happening, and gave the seemingly ludicrous advice to revert back to a Big Flat Bridged Network. They were actually saying something else, but we misinterpreted. As of today, the customer is testing, without the superscope in place, and all appears well. Win2K and WinXP workstations are mobile, and are behaving the way many of you described as proper. See- the problem is always a server problem. It's NEVER the routers.... ;-> Chuck ""Priscilla Oppenheimer"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Evans, TJ wrote: > > > > IIRC: > > Win2k and later detect 'cable disconnects', and de-IP your > > system. > > > > Strangely, they also detect 'cable reconnects' and attempt to > > re-IP (via > > DHCP, or autoconfig if enabled) you at that time. > > Not to beat this to death, but that must indeed be the explanation. W2K and > XP recognize when the user connects the Ethernet cable and resend a DHCP > request, assuming DHCP is being used. So when the PC is moved to a new > location and new subnet, it gets a proper address without any user twidling > beyond inserting the cable. This seems too smart for Windoze, but I can't > think of any other explanataion. > > So, Chuck's users are using W2K and XP. What could they be doing wrong?? > > Also, of course, this doesn't solve the problem for wireless users. That's > not what Chuck was asking about, but it's still an interesting issue. They > could benefit from Mobile IP. (I really want to recommend that. ;-) > > The reason I say that the cable insertion theory is the explanation is that > there's no other way for the operating system and protocol stack to know > that it needs to send a new DHCP request. Remember, we're talking about > laptops that haven't been shut down. (Maybe they go to sleep though? Awaking > from sleep might also cause a new DHCP request?) > > The PC can't tell that it's on a different network by just looking at > packets. Even though it could see the IP addresses being used by other > devices, it couldn't know the subnet mask and default gateway to use. > > Contrast this with AppleTalk, which solved this problem years ago. ;-) An > AppleTalk end node hears the incessant RTMPs coming from routers. Not only > does the end node learn the address of a gateway to use from that, but it > also learns its own network number because the local net number is always > the first one in the RTMP packet. Of course, the tradeoff was those > incessant RTMPs. ;-) But moving a Mac to a new network has always been > pretty straightforward, despite a rather annoying message that comes up and > confuses users. > > _______________________________ > > Priscilla Oppenheimer > www.troubleshootingnetworks.com > www.priscilla.com > > > > > > Thanks! > > TJ > > > > > > -----Original Message----- > > From: Larry Letterman [mailto:[EMAIL PROTECTED]] > > Sent: Tuesday, October 01, 2002 1:20 PM > > To: [EMAIL PROTECTED] > > Subject: Re: OT: Serves Me Right - DHCP problem [7:54402] > > > > Nothing to fess up to, Chuck..My w2K works the same way at > > home.. > > connect, get a number..disconnect and reconnect , get a > > different number.. > > Linksys routers are pretty simple devices...I have two of them > > currently > > and > > both give out dhcp on different subnets...I can get an address > > from > > either one > > by the above function....no mobile ip..no special setup..just > > like > > Darrell said... > > > > Larry > > > > Chuck's Long Road wrote: > > > > >well S*** Larry, thanks for providing that vital piece of > > troubleshooting > > >relevant information! > > > > > >I still say you are using Mobile IP. > > > > > >fess up ;-> > > > > > >Chuck > > > > > >-- > > > > > >www.chuckslongroad.info > > >like my web site? > > >take the survey! > > > > > > > > > > > >""Larry Letterman"" wrote in message > > >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > > >>thats why we put in wireless in all our buildings..moving > > around is no > > >>problem... > > >> > > >>Priscilla Oppenheimer wrote: > > >> > > >>>Darrell Newcomb wrote: > > >>> > > >>>>Because pre-W2K windows didn't automatically try to renew a > > >>>>lease when the > > >>>>ethernet interface comes back up after being down. So...if > > the > > >>>>old lease > > >>>>hadn't come up for renewal during the time the machine moved > > >>>> > > >>>>from point A to > > >>> > > >>>>B.....the users don't automatically get connectivity. > > >>>> > > >>>Plus with laptops, the user expects to not have to reboot. > > They may just > > >>>move from building to building without shutting down the > > laptop. It might > > >>> > > >go > > > > > >>>to sleep, but you should just be able to hit a button and > > keep working. > > >>> > > >It > > > > > >>>seems like a reasonable user expectation, but alas, we as > > networkers > > >>> > > >haven't > > > > > >>>done a good job in this area. (at least with IP) > > >>> > > >>>The technical issue is that the user is in a different > > subnet and needs a > > >>>new IP address and default gateway after moving to a new > > building, > > >>> > > >location, > > > > > >>>whatever. > > >>> > > >>>Priscilla > > >>> > > >>>>Lots of options to teach the helpdesk how to educate > > >>>>users....but since it > > >>>>'worked before' in Chuck's case it's seen as a (big?) > > >>>>problem(PITA). > > >>>> > > >>>>""Larry Letterman"" wrote in message > > >>>>[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > >>>> > > >>>>>why is that ? we have segmented avvid network across our > > >>>>> > > >>>>campus. The > > >>>> > > >>>>>laptops are all W2K and they work just > > >>>>>fine without any issues on DHCP...The routers are all > > running > > >>>>> > > >>>>hsrp and > > >>>> > > >>>>>work correctly.. > > >>>>> > > >>>>>Chuck's Long Road wrote: > > >>>>> > > >>>>>>I see I should have made this one a "Friday Folly" :-> > > >>>>>> > > >>>>>>In a Big Flat Bridged Network, a mobile user unplugs the > > >>>>>> > > >>>>laptop at one > > >>>> > > >>>>>>office, drives over to the next office, plugs back in, and > > >>>>>> > > >>>>no further > > >>>>action > > >>>> > > >>>>>>is required. The Windoze PC has retained it's IP address, > > >>>>>> > > >>>>and the network > > >>>> > > >>>>>>doesn't care about location, because it is one big flat > > >>>>>> > > >>>>network. > > >>>> > > >>>>>>However, in the brand new ATM based AVVID ready routed > > >>>>>> > > >>>>network, said > > >>>>mobile > > >>>> > > >>>>>>user is now in a different segment in each location. With > > >>>>>> > > >>>>Windoze, you > > >>>>have > > >>>> > > >>>>>>to manually intervene. Sometimes you have to release the > > IP > > >>>>>> > > >>>>address, > > >>>>reload > > >>>> > > >>>>>>the computer, and then get your new DHCP assignment. Users > > >>>>>> > > >>>>don't like > > >>>>this. > > >>>> > > >>>>>>After all, now they have to do something, whereas before > > >>>>>> > > >>>>they did not. > > >>>>Never > > >>>> > > >>>>>>mind the higher speed, the failover capability of the > > >>>>>> > > >>>>routers, the new > > >>>>100 > > >>>> > > >>>>>>mbs switches rather than 10mbs. They have to take an extra > > >>>>>> > > >>>>step or two in > > >>>> > > >>>>>>order to log in. > > >>>>>> > > >>>>>>This is normal behaviour for Windoze machines, and maybe > > for > > >>>>>> > > >>>>DHCP clients > > >>>>in > > >>>> > > >>>>>>general. I have had to do this release / renew for years. > > >>>>>> > > >>>>>>But to the customer, who is pretty naive in terms of > > >>>>>> > > >>>>networking, there is > > >>>>a > > >>>> > > >>>>>>"problem" that was caused by the new routers. To the > > users, > > >>>>>> > > >>>>there is a > > >>>> > > >>>>>>problem that never existed before. > > >>>>>> > > >>>>>>Like I said, serves me right. You give a customer a great > > >>>>>> > > >>>>new network, > > >>>>and > > >>>> > > >>>>>>you break something so rudimentary that it never would > > have > > >>>>>> > > >>>>occurred > > >>>> > > >>>>>>otherwise. :-> > > >>>>>> > > >>>>>>-- > > >>>>>> > > >>>>>>www.chuckslongroad.info > > >>>>>>like my web site? > > >>>>>>take the survey! > > >>>>>> > > >>>>>> > > >>>>>> > > >>>>>>""Priscilla Oppenheimer"" wrote in message > > >>>>>>[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > >>>>>> > > >>>>>>>Spare us the mystery and tell us what you're getting at. > > >>>>>>> > > >>>>:-) Did you > > >>>> > > >>>>>>forget > > >>>>>> > > >>>>>>>to tell the DHCP server to provide the correct default > > >>>>>>> > > >>>>gateway address > > >>>>to > > >>>> > > >>>>>>>the PCs? That's my guess, since you say everything else > > >>>>>>> > > >>>>like helper > > >>>> > > >>>>>>>addresses, etc. is configured correctly. Just a > > late-night > > >>>>>>> > > >>>>theory, > > >>>> > > >>>>>>waiting > > >>>>>> > > >>>>>>>for Jay Leno to come on..... > > >>>>>>> > > >>>>>>>Thanks, > > >>>>>>> > > >>>>>>>Priscilla > > >>>>>>> > > >>>>>>>Chuck's Long Road wrote: > > >>>>>>> > > >>>>>>>>The AVVID solution I sold a few months ago is gong > > through > > >>>>>>>>implementation. > > >>>>>>>>This project has been problematic for a lot of reasons, > > so > > >>>>>>>> > > >>>>it > > >>>> > > >>>>>>>>is not unusual > > >>>>>>>>for a round of e-mails from the customer complaining > > about > > >>>>>>>> > > >>>>one > > >>>> > > >>>>>>>>thing or > > >>>>>>>>another. > > >>>>>>>> > > >>>>>>>>Today was a good one, however. Shows to go you have to > > ask > > >>>>>>>>things you > > >>>>>>>>normally wouldn't think about. > > >>>>>>>> > > >>>>>>>>DHCP - no big deal. Works fine. All of us have probably > > >>>>>>>> > > >>>>used it > > >>>> > > >>>>>>>>or > > >>>>>>>>configured it. All of us probably have experience with > > >>>>>>>> > > >>>>running > > >>>> > > >>>>>>>>several small > > >>>>>>>>sites off a single DHCP server at a central site. > > >>>>>>>> > > >>>>>>>>So why is the customer complaining about DHCP not > > working, > > >>>>>>>> > > >>>>and > > >>>> > > >>>>>>>>it's because > > >>>>>>>>our routers are screwed up and Microsoft told them that > > >>>>>>>> > > >>>>they > > >>>> > > >>>>>>>>would have to > > >>>>>>>>change their network addressing to a single class B > > rather > > >>>>>>>> > > >>>>than > > >>>> > > >>>>>>>>subnets of > > >>>>>>>>/16 space, the way I designed it? > > >>>>>>>> > > >>>>>>>>The routers are configured correctly. The network is > > >>>>>>>> > > >>>>designed > > >>>> > > >>>>>>>>correctly - no > > >>>>>>>>overlapping subnets. IP helpering is configured > > correctly. > > >>>>>>>> > > >>>>>>>>Problem occurs with several users, different NIC's, > > either > > >>>>>>>>Win2K or WinXP. > > >>>>>>>>No one common factor. Worked just fine before we put the > > >>>>>>>> > > >>>>new > > >>>> > > >>>>>>>>routers in. > > >>>>>>>> > > >>>>>>>>Recognizing that Microsoft is full of C**P and their TCP > > >>>>>>>> > > >>>>stack > > >>>> > > >>>>>>>>is S**T, > > >>>>>>>>still, why the problem. > > >>>>>>>> > > >>>>>>>>Gee, what happens to DHCP when you go from a single flat > > >>>>>>>>bridged network to > > >>>>>>>>a segmented routed network? Especially to mobile users, > > who > > >>>>>>>>travel from site > > >>>>>>>>to site for various reasons on a regular basis? > > >>>>>>>> > > >>>>>>>>Serves me right > > >>>>>>>> > > >>>>>>>>Chuck > > >>>>>>>> > > >>>>>>>>-- > > >>>>>>>> > > >>>>>>>>www.chuckslongroad.info > > >>>>>>>>like my web site? > > >>>>>>>>take the survey! > > >>>>>>>> > > >>>>>-- > > >>>>> > > >>>>>Larry Letterman > > >>>>>Network Engineer > > >>>>>Cisco Systems Inc. > > >>>>> > > >>-- > > >> > > >>Larry Letterman > > >>Network Engineer > > >>Cisco Systems Inc. > > > **************************************************************************** * > > The information in this email is confidential and may be > > legally privileged. > > It is intended solely for the addressee. 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